<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            height: 200px;
            width: 200px;
            background-color: pink;
        }
    </style>
</head>

<body>
    <div></div>
    <script>
        //一.更改里面的颜色 element.style  行内样式操作
        //1.获取元素
        var div = document.querySelector('div');
        //2.注册事件 处理程序
        div.onclick = function() {
            //div.style里面的属性 采取驼峰命名法
            this.style.backgroundColor = 'yellow';
            this.style.height = '100px'; //改变大小
        }
    </script>
</body>

</html>